Continue study of inhibitors produced in tissues, particularly of inhibitors which may participate in the regulation of fibrinolysis by inhibiting the conversion of a plasminogen proactivator designated preurokinase. BIBLIOGRAPHIC REFERENCE: Bernik, M.B. and Oller, E.P. Plasminogen activator and proactivator (urokinase precursor) in lung cultures. In press, J. Amer. Med. Women's Assoc., l976.